1. Field of the Invention
The present invention relates generally to the field of telecommunications and, more specifically, to a programmable telecommunications switch which is operable as a node in an expandable telecommunications system and includes an interface for conducting telecommunications over the Internet.
2. Discussion of the Related Art
With the goal of providing telecommunication services at lower prices than those charged by long distance carriers, competitive local exchange carriers (CLECs) and government-controlled telephone companies, an effort is underway to use the Internet to carry voice traffic which has traditionally been carried by the public switched telephone network (PSTN). This type of application or service is often referred to as xe2x80x9cvoice over IPxe2x80x9d (VoIP) where xe2x80x9cIPxe2x80x9d refers to Internet protocol.
Several important considerations arise in connection with the development of VoIP including determining how much, if any, of a communication path from a given subscriber to another should be provided by the PSTN and how much should be provided by the Internet. In other words, should a subscriber""s communication device interface directly with the Internet (meaning that subscribers must be equipped with xe2x80x9cInternet telephones,xe2x80x9d PCs which include telephone functionality or the like), or should the PSTN be used to connect subscribers (who would continue to use conventional telephone sets) to the Internet through a gateway or similar device. Of course, other scenarios are possible as well, and it is likely that a mixed or hybrid infrastructure will exist for a long time because of the prohibitive cost of constructing or replacing networks as well as replacing subscriber equipment.
Another consideration is how to provide supplementary or enhanced services to subscribers who will not want to sacrifice call forwarding, call-waiting, voicemail, conference calling and other existing services merely to obtain lower cost Internet-based phone service. Further, there is great need for system flexibility to allow rapid, inexpensive development and introduction of new services, largely because such new services provide large revenue growth potential for most carriers.
A third consideration is system capacity and scalability. Because of the difficulty in accurately forecasting both the demand for additional telecommunication bandwidth and the rate at which subscribers will migrate to Internet-based telephony, it is extremely important that any system be capable of rapid, large-scale expansion without significant disruption of service and without forcing large initial investment for capacity that may not be needed for a long time.
In brief summary, the present invention provides a programmable telecommunication switch, operable as a node in an expandable telecommunications system, as a standalone switch, or as a gateway. The programmable switch includes an interface, sometimes referred to as a voice/data concentrator card, for conducting VoIP communications. One side of the interface connects to the Internet or other packet-based network, while the other side of the interface connects with the switch""s internal bus structure over which the interface and other circuitry within the switch may communicate.
The present invention permits a CLEC, system integrator or other customer to introduce VoIP capability as either an addition to an existing network (e.g., PSTN) or through the construction of a new network as desired. In either case, the present invention allows the introduction of VoIP capability in the locations and amounts needed to satisfy demand. Future growth in demand for such capacity is flexibly accommodated by simply including additional interfaces within the switch or adding additional nodes as the case may be. If desired, multiple interfaces may be concentrated in a single node whose VoIP capability is fully accessible by the other nodes of the expandable telecommunications system. Similar considerations apply to using the present invention to provide communications based on protocols other than IP.
In addition, traditional telephony services and functions, including both supplementary services (conferencing, call waiting, voicemail, etc.) and network signalling (tone detection, tone generation, etc.), as well as new services, may be provided within the same programmable switch which includes a VoIP capability or within other nodes that are part of the same expandable telecommunications system.